Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/04—Wireless resource allocation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
  • H04L1/0016—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy involving special memory structures, e.g. look-up tables

Definitions

• the present disclosure relates to wireless data communications.
• wireless computing devices such as portable wireless telephones, personal digital assistants (PDAs), and paging devices that are small, lightweight, and easily carried by users.
• portable wireless telephones such as cellular telephones and Internet Protocol (IP) telephones
• IP Internet Protocol
• a wireless telephone can also include a digital still camera, a digital video camera, a digital recorder, and an audio file player.
• wireless telephones can execute software applications, such as a web browser application that can be used to access the Internet. As such, these wireless telephones can include significant computing capabilities.
• networks may be used to exchange
• Networks may be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks may be designated respectively as a wide area network (WAN), a metropolitan area network (MAN), a local area network (LAN), a wireless local area network (WLAN), or a personal area network (PAN). Networks may also differ according to the switching/routing techniques used to interconnect the various network nodes and devices (e.g., circuit switching vs. packet switching), the type of physical media employed for transmission (e.g., wired vs.
• WAN wide area network
• MAN metropolitan area network
• LAN local area network
• WLAN wireless local area network
• PAN personal area network
• Networks may also differ according to the switching/routing techniques used to interconnect the various network nodes and devices (e.g., circuit switching vs. packet switching), the type of physical media employed for transmission (e.g., wired vs.
• Wireless networks may be preferred when network elements are mobile and have dynamic connectivity needs or if the network architecture is formed in an ad hoc, rather than fixed, topology.
• Wireless networks may employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, or other frequency bands. Wireless networks may advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.
• Devices in a wireless network may transmit/receive information with other devices/systems.
• the information may include packets.
• the packets may include overhead information (e.g., header information, packet properties, etc. related to routing the packets through the network) as well as data (e.g., user data, multimedia content, etc. in a payload of the packet).
• overhead information e.g., header information, packet properties, etc. related to routing the packets through the network
• data e.g., user data, multimedia content, etc. in a payload of the packet.
• IEEE 802.1 1 is a set of industry standards, protocols, and groups associated with wireless networking.
• IEEE 802.11a, 802.1 lb, 802.1 lg, and 802.1 In are wireless networking standards that may be used in customer premise wireless networking, such as in a home or office environment.
• "In progress" IEEE 802.11 standards include 802.1 lac (entitled “Very High Throughput in ⁇ 6 GHz"), 802.1 lad (entitled “Very High Throughput in 60 GHz”), 802. l laf (entitled “Wireless Local Area Network (LAN) in Television White Space”), and 802.1 lah (entitled “Sub-1 GHz”).
• IEEE 802.1 lah is associated with wireless communication at frequencies less than one gigahertz. Such communication may be useful for devices having low duty cycles, such as sensors.
• a wireless sensor that communicates over an IEEE 802.1 lah network may wake up for a few seconds to perform a few measurements, communicate results of the measurements to a destination, and then sleep for a few minutes.
• An IEEE 802.1 lah wireless network may support communication using 1, 2, 3, or 4 spatial streams at 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths.
• GHz networks e.g., IEEE 802.1 lah networks
• MCS modulation and coding scheme
• More than one MCS may be available for each bandwidth/spatial stream combination.
• An index value corresponding to the chosen MCS may be included in the message.
• an MCS index may be included in a signal (SIG) field of a physical layer (PHY) preamble of the message.
• SIG signal
• PHY physical layer
• the receiver may use the MCS index to determine various message characteristics that may be useful in decoding the message.
• the transmitter and the receiver may each store or otherwise have access to data structures (e.g., tables) that can be searched by MCS index.
• Packets communicated via a sub-1 GHz wireless network may comply with one of multiple frame formats (e.g., a single user (SU) or "short” format and a multi user (MU) or "long” format) and may comply with various timing parameters.
• the frame format may identify what fields are included in the packet and the order of the fields in the packet.
• the timing parameters may indicate quantities and field durations associated with the packet.
• the frame format and/or timing parameters may be used in encoding and/or decoding of the packet.
• a data structure e.g., table
• indicating timing parameters for different frame formats may be stored at or otherwise accessible to transmitters and receivers.
• Packets communicated via a sub-1 GHz wireless network may also be
• tone scaling parameters may be used in encoding and/or decoding of the packet.
• a data structure e.g., table
• tone scaling parameters for different fields may be stored at or otherwise accessible to transmitters and receivers.
• a non-transitory processor-readable medium stores one or more data structures for use during communication via a sub-one gigahertz wireless network.
• the one or more data structures correspond to one or more available bandwidths of the sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network.
• the one or more available bandwidths of the sub-one gigahertz wireless network include a one megahertz bandwidth.
• Each data structure indicates, for each of a plurality of modulation and coding scheme (MCS) indexes: a modulation scheme of a packet that includes the MCS index, a coding rate to encode the packet, a number of bits per subcarrier symbol in the packet, a number of data symbols in the packet, and a number of pilot symbols in the packet.
• MCS modulation and coding scheme
• a method includes selecting, at a
• the sub-one gigahertz wireless network supports operation at a bandwidth of one megahertz.
• the method also includes determining at least one encoding characteristic based on an MCS index corresponding to the selected MCS.
• the method further includes inserting the MCS index into the packet, encoding the packet based on the at least one encoding characteristic, and sending the encoded packet to a receiver.
• a method in another particular embodiment, includes receiving a packet via a sub-one gigahertz wireless network operating at a particular bandwidth while using a particular number of spatial streams.
• the sub-one gigahertz wireless network supports operation a bandwidth of one megahertz.
• the method also includes extracting a modulation and coding scheme (MCS) index from the received packet.
• MCS modulation and coding scheme
• the method further includes identifying a data structure stored at the receiver, the data structure corresponding to the particular bandwidth and the particular number of spatial streams.
• the method includes determining, based the extracted MCS index and the identified data structure, at least one encoding characteristic of the received packet.
• the method also includes decoding the received packet based on the at least one encoding characteristic.
• an apparatus in another particular embodiment, includes a memory storing one or more data structures.
• the data structures correspond to bandwidths and spatial streams of a sub-one gigahertz wireless network.
• the one or more available bandwidths of the sub-one gigahertz wireless network include a one megahertz bandwidth.
• Each data structure indicates, for each of a plurality of MCS indexes, at least one encoding characteristic of a packet that includes the MCS index.
• the apparatus also includes a processor coupled to the memory and configured to extract a first MCS index from a first packet received via the sub-one gigahertz wireless network operating at a first bandwidth while using a first number of spatial streams.
• the processor is also configured to determine, based on a search of the first MCS index in a first data structure of the plurality of data structures that corresponds to the first bandwidth and the first number of spatial streams, at least one encoding characteristic of the received packet.
• an apparatus includes means for storing one or more data structures.
• the one or more data structures correspond to one or more available bandwidths of a sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network.
• the one or more available bandwidths of the sub-one gigahertz wireless network include a one megahertz bandwidth.
• Each data structure indicates, for each of a plurality of MCS indexes, at least one encoding characteristic of a packet that includes the MCS index.
• the apparatus also includes means for processing a packet based on a particular MCS index included in the packet.
• embodiments is an ability to control various characteristics of messages (e.g., packets) communicated via a sub-1 GHz wireless network.
• characteristics may include MCS, frame format, timing parameters, tone scaling parameters, and/or other characteristics described herein.
• FIG. 1 is a diagram of a particular embodiment of a system operable to
• FIGS. 2-8 illustrate particular examples of the MCS tables of FIG. 1 ;
• FIGS. 9-10 illustrate particular examples of the MCS tables of FIG. 1 when a single encoder is used for all possible bandwidths and numbers of spatial streams;
• FIG. 11 is a flowchart of a particular embodiment of a method of
• FIG. 12 is a flowchart of a particular embodiment of a method of controlling message characteristics in a sub-1 GHz wireless network based on an MCS index;
• FIG. 13 is a diagram to illustrate particular embodiments of frame formats that may be used to with respect to the packet of FIG. 1;
• FIG. 14 illustrates particular examples of the timing parameters of FIG. 1;
• FIG. 15 is a flowchart of a particular embodiment of a method of controlling a frame format and timing parameters in a sub-1 GHz wireless network
• FIG. 16 illustrates particular examples of the tone scaling parameters of
• FIG. 1 A first figure.
• FIG. 17 is a flowchart of a particular embodiment of a method of controlling tone scaling parameters in a sub-1 GHz wireless network.
• FIG. 18 is a block diagram of a mobile communication device including components that are operable to control characteristics of messages in a sub-1 GHz wireless network.
• FIG. 1 is a diagram of a particular embodiment of a system 100 operable to control message characteristics in a sub-1 GHz wireless network 140.
• the sub-1 GHz wireless network 140 operates in accordance with an IEEE 802.1 lah protocol.
• the wireless network 140 may support multiple bandwidths and one or more spatial streams.
• the wireless network 140 may support 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths and the use of 1, 2, 3, or 4 spatial streams.
• the system 100 includes a transmitter 1 10 and a receiver 120. It should be noted that although a single transmitter and receiver are shown in FIG. 1 , alternate embodiments may include more than one transmitter and or receiver.
• the transmitter 1 10 and the receiver 120 may communicate via packets, such as an illustrative packet 130. It should be noted that although a dedicated transmitter 110 and a dedicated receiver 120 are shown in FIG. 1, some devices (e.g., transceivers or mobile communication devices that include a transceiver) may be capable of both packet transmission as well as packet reception. Thus, the wireless network 140 supports two- way communication.
• the transmitter 110 may store or otherwise have access to MCS tables 1 1 1, timing parameters 1 12, and tone scaling parameters 113.
• the transmitter 1 10 may include a packet creator/encoder 114 that is configured to create and encode packets, such as the packet 130. The creator/encoder 114 may set one or more characteristics of the packet 130 during the creation and encoding process.
• the creator/encoder 114 may select a particular modulation and coding scheme (MCS) of the packet 130 from a plurality of available MCSs. Which MCSs are available may depend on the bandwidth and the number of spatial streams in use at the wireless network 140.
• MCSs modulation and coding scheme
• devices connected to the wireless network 140 may be notified of the bandwidth and number of spatial streams by an access point associated with the wireless network (e.g., via a beacon, probe response, or other control message). Devices may also determine network
• the transmitter 1 10 may store or otherwise have access to one or more MCS tables 11 1 that identify the available MCSs for each combination of bandwidth and number of spatial streams.
• the creator/encoder 1 14 may insert an index of the selected MCS into the packet 130.
• the MCS index may be included in a signal (SIG) field of a physical layer (PHY) preamble of the packet 130.
• the MCS index may indicate a modulation scheme and a coding rate of the packet 130 and may also indicate or be useable to derive additional encoding characteristics of the packet 130, such as a number of bits per subcarrier symbol, a number of data symbols, a number of pilot symbols, a number of coded bits per orthogonal frequency-division multiplexing (OFDM) symbol, a number of data bits per (OFDM) symbol, a number of encoders used to encode the packet 130, data rate(s), and/or a guard interval.
• OFDM orthogonal frequency-division multiplexing
• the receiver 120 may store or otherwise have access to MCS tables 121, timing parameters 122, and tone scaling parameters 123, which may be the same as the MCS tables 1 11, the timing parameter 112, and the tone scaling parameters 113, respectively.
• the receiver 120 may include a packet extractor/decoder 124 that is configured to process received packets, such as the received packet 130. For example, the extractor/decoder 124 may extract the MCS index from the packet 130.
• the extractor/decoder 124 may identify a particular MCS table of the MCS tables 121 that corresponds to the bandwidth and number of spatial streams in use at the wireless network 140, and may search for characteristic values in the particular MCS table corresponding to the extracted MCS index. Based on the search, the extractor/decoder 124 may determine one or more encoding characteristics of the packet 130 and may decode the packet 130 based on the encoding characteristic(s).
• the packet 130 may comply with one of multiple frame formats (e.g., a single user (SU) or "short” format and a multi user (MU) or "long” format) and may comply with various timing parameters.
• the frame format is selected by the transmitter 1 10 or specified by the receiver 120.
• the frame format may identify fields to be included in the packet 130 and the order of the fields in the packet 130.
• the timing parameters may indicate quantities and field durations associated with the packet 130.
• the frame format and/or timing parameters may be used in encoding and/or decoding of the packet 130.
• a data structure e.g., table
• indicating timing parameters for different frame formats may be stored at or otherwise accessible to transmitters and receivers.
• the timing parameters may be stored in a table or array in a memory at the transmitter 110 as the timing parameters 112 and at the receiver 120 as the timing parameters 122.
• the frame format used for the packet 130 is based at least in part on whether the underlying sub-1 GHz wireless network 140 is operating at 1 MHz bandwidth. For example, only the SU frame format may be available when the bandwidth is 1 MHz, but both the SU frame format and the MU frame format may be available for bandwidths greater than 1 MHz. In a particular embodiment, certain field durations may be longer when the bandwidth is 1 MHz than when the bandwidth is greater than 1 MHz. Examples of frame formats and timing parameters are further described with reference to FIGS. 13-14.
• the packet 130 may also be subjected to tone scaling. For example,
• Tone scaling parameters may be used in encoding and/or decoding of the packet.
• a data structure e.g., table
• indicating tone scaling parameters for different fields may be stored at or otherwise accessible to transmitters and receivers.
• the tone scaling parameters may be stored in a table or array in a memory at the transmitter 110 as the tone scaling parameters 113 and at the receiver 120 as tone scaling parameters 123.
• different tone scaling parameters may be used based on whether the packet 130 is represented in the SU frame format or in the MU frame format. Examples of tone scaling parameters are further described with reference to FIG. 16.
• the transmitter 1 10 may create and encode the packet 130 based on a selected MCS index and encoding characteristics associated therewith, a selected frame format, selected timing parameters, and/or selected tone scaling parameters.
• the bandwidth and number of spatial streams in use at the underlying sub- 1 GHz wireless network 140 may also impact the creation and encoding of the packet 130.
• the bandwidth and number of spatial streams may affect what MCS indexes are available, what frame formats are available, and the values, or permitted range of values, of certain timing and tone scaling parameters.
• the receiver 120 may use the MCS index, the frame format, the timing parameters, and/or the selected tone scaling parameters in processing (e.g., decoding) the packet 130.
• the system 100 of FIG. 1 may thus provide standardized values of MCS indexes, frame formats, timing parameters, tone scaling parameters, and other message characteristics for use in a sub-1 GHz wireless network (e.g., an IEEE 802.1 lah wireless network), where such values vary based on characteristics (e.g., bandwidth and number of spatial streams) of the wireless network.
• Standardizing such PHY (e.g., Layer-1) and media access control (MAC) (e.g., Layer-2) messaging characteristics may enable reliable communication via the sub-1 GHz wireless network.
• FIGS. 2A-2C illustrate examples of the MCS tables 11 1 and the MCS tables
• FIGS. 2A-2C illustrate MCS tables for a sub-1 GHz wireless network operating at 1 MHz bandwidth while using 1 spatial stream.
• MCS tables may include message characteristics for each of a plurality of
• the MCS tables may indicate a modulation scheme ("Mod"), a coding rate ("R”), a number of bits per subcarrier symbol (“N_bpscs”), a number of data symbols (“N_sd”), and/or a number of pilot symbols (“N_sp”) for each MCS index (“MCS Idx").
• the MCS tables may also indicate a number of coded bits per OFDM symbol (“N_cbps”), a number of data bits per OFDM symbol (“N_dbps”), a number of encoders used (“N_es”), data rate(s), and/or a guard interval ("GI”).
• Data rates may vary depending on whether an eight microsecond guard interval or a four microsecond guard interval is used.
• the number of coded bits per OFDM symbol may be derivable in accordance with the formula
• N_cbps N_sd * N_bpscs.
• the number of encoders may be determined based on the formula
• N_es ceiling(Data Rate/60 Mbps), where ceiling() is the integer ceiling function. In some situations, the formula for N_es may be modified, as further described herein.
• an MCS index for a given bandwidth is an MCS index for a given bandwidth
• N_cbps/N_es is a non-integer
• N_dbps/N_es is a non- integer
• N_dbps is a non-integer
• Such MCS indexes may be made unavailable for implementation simplicity (e.g., so that puncture patterns are consistent between OFDM symbols and so that extra padding symbols are not needed after puncturing/rate-matching).
• the number of encoders N_es may be modified so that N_cbps/N_es and/or N_dbps/N_es become integers, as further described herein.
• each packet communicated via a sub-1 GHz network may include an MCS index.
• the repeat MCS scenario may have an MCS index of 15 (i.e., -1 when a 4-bit MCS index is interpreted as two's complement).
• FIGS. 3A-3C illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 3A-3C illustrate MCS tables for a sub-1 GHz wireless network operating at 1 MHz bandwidth while using 2, 3, or 4 spatial streams.
• FIGS. 4A-4D illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 4A-4D illustrate MCS tables for a sub-1 GHz wireless network operating at 2 MHz bandwidth while using 1, 2, 3, or 4 spatial streams.
• MCS index 9 may be unavailable when operating at 2 MHz using 1, 2, or 4 spatial streams, because N_dbps may be a non-integer.
• MCS indexes that are unavailable may be indicated as unavailable by being flagged (e.g., using an availability bit) or removed from an MCS table.
• FIGS. 5A-5D illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 5A-5D illustrate MCS tables for a sub-1 GHz wireless network operating at 4 MHz bandwidth while using 1, 2, 3, or 4 spatial streams.
• FIGS. 6A-6D illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 6A-6D illustrate MCS tables for a sub-1 GHz wireless network operating at 8 MHz bandwidth while using 1, 2, 3, or 4 spatial streams.
• MCS index 6 may be unavailable when operating at 8 MHz using 3 spatial streams, because N_dbps/N_es may be a non- integer.
• FIGS. 7A-7D illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 7A-7D illustrate MCS tables for a sub-1 GHz wireless network operating at 16 MHz bandwidth while using 1, 2, or 3 spatial streams.
• MCS index 9 is unavailable, because N_dbps/N_es is a non-integer.
• N_es may be increased from 5 to 6 for MCS index 9, which changes N_dbps/N_es to an integer quantity and makes MCS index 9 available.
• the number of encoders may be modified to make certain MCS indexes available. In devices that would otherwise not use six encoders, this modification may result in the addition of an encoder. However, in devices that use six encoders for other bandwidth/spatial stream combinations (e.g., devices that support 4 spatial streams at 16 MHz, as shown in FIG. 8), this modification may be performed without adding additional hardware.
• FIGS. 8A-8B illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 8A-8B illustrate MCS tables for a sub-1 GHz wireless network operating at 16 MHz bandwidth while using 4 spatial streams.
• N_es may be increased from 5 to 6 for MCS index 7, which changes N_cbps/N_es to an integer quantity and makes MCS index 7 available.
• a single encoder may be used for all
• MCS tables that include at least one row with N_es > 1 may be modified, as shown in FIGS. 9-10.
• FIGS. 9A-9D illustrate examples of the MCS tables 1 11 and the MCS tables
• FIGS. 9A-9D illustrate MCS tables for a sub-1 GHz wireless network operating at 4 MHz bandwidth while using 4 spatial streams and at 8 MHz bandwidth while using 2, 3, or 4 spatial streams, with a single encoder.
• FIGS. 10A-10D illustrate additional examples of the MCS tables 1 11 and the
• FIGS. 10A-10D illustrate MCS tables for a sub-1 GHz wireless network operating at 16 MHz bandwidth while using 1, 2, 3, or 4 spatial streams with a single encoder.
• FIG. 11 is a flowchart of a particular embodiment of a method 1100 of determining message characteristics based on an MCS index in a sub-1 GHz wireless network.
• the method 1 100 may be performed by the receiver 120 of FIG. 1.
• the method 1100 may include receiving, at a receiver from a transmitter, a packet via a sub- 1 GHz wireless network operating at a particular bandwidth while using a particular number of spatial streams, at 1 102.
• the wireless network may be an IEEE 802.1 lah network.
• the receiver 120 may receive the packet 130 from the transmitter 110 via the wireless network 140.
• the method 1100 may also include extracting an MCS index from the
• the data structure may correspond to the particular bandwidth and the particular number of spatial streams.
• the MCS index may be extracted from a SIG field of a PHY preamble of the packet.
• the extractor/decoder 124 may extract an MCS index from the packet 130 and may identify one of the MCS tables 121 that corresponds to the bandwidth and number of spatial streams.
• the identified MCS table may be the table at the top of FIG. 5.
• the method 1100 may further include determining, based on searching the identified data structure for characteristic values corresponding to the extracted MCS index, at least one encoding characteristic of the received packet, at 1108.
• the encoding characteristic may include a modulation scheme, a coding rate, a number of bits per subcarrier symbol, a number of data symbols, a number of pilot symbols, a number of coded bits per OFDM symbol, a number of data bits per OFDM symbol, a number of encoders, data rate(s), and/or a guard interval.
• the extracted MCS index is 5 it may be determined from the table at the top of FIG.
• the method 1 100 may include decoding the packet based on the at least one encoding characteristic.
• the extractor/decoder 124 may decode the packet 130 based on the at least one encoding characteristic.
• the type of demodulation e.g., binary phase-shift keying (BPSK), quadrature PSK (QPSK), quadrature amplitude modulation (QAM), etc.
• BPSK binary phase-shift keying
• QPSK quadrature PSK
• QAM quadrature amplitude modulation
• FIG. 12 is a flowchart of a particular embodiment of a method 1200 of
• the method 1200 may be performed by the transmitter 110 of FIG. 1.
• the method 1200 may include selecting, at a transmitter, an MCS from a plurality of MCSs available for use in communicating a packet via a sub-1 GHz wireless network operating at a particular bandwidth while using a particular number of spatial streams, at 1202.
• the transmitter 1 10 may select an available MCS from one of the MCS tables 11 1 that corresponds to the bandwidth and number of spatial streams in use.
• the method 1200 may also include determining at least one encoding
• the method 1200 may further include inserting the MCS index into the packet, at 1206, and encoding the packet based on the at least one encoding characteristic, at 1208.
• the creator/encoder 114 may insert the MCS index into the packet 130 and encode the packet 130.
• the method 1200 may include sending the encoded packet to a receiver, at 1210.
• the transmitter 110 may send the packet 130 to the receiver 120.
• FIG. 13 is a diagram to illustrate particular embodiments of frame formats that may be used to represent the packet 130 of FIG. 1 and is generally designated 1300.
• packets transmitted via a sub-1 GHz network may comply with one of multiple frame formats, such as a single user (SU) frame format 1310 or a multi user (MU) frame format 1320.
• SU single user
• MU multi user
• Each frame format 1310, 1320 may specify fields that are to be included in a packet and the order of such fields.
• the SU frame format 1310 may include a short training field (STF) 1311, a long training field (LTF) 1312 (LTF_1), and a SIG field 1313.
• STF short training field
• LTF long training field
• SIG field 1313 SIG field 1313
• additional LTFs 1314 e.g., one additional LTF for each additional spatial stream.
• the STF 1311, the LTF 1312, the SIG field 1313, and the additional LTFs 1314 may represent a packet preamble.
• the SU frame format 1310 may also include a data portion 1315.
• the MU frame format 1320 may include two portions: a first portion without precoding (designated as an omni portion 1330) and a second portion with precoding (designated as an MU portion 1340).
• the omni portion 1330 may include a STF 1321, a first LTF 1322 (LTF_1), and a signal A (SIG-A) field 1323.
• the MU 1340 portion may include an additional STF 1324 and, when more than one spatial stream is in use, one or more additional LTFs 1325.
• the MU portion 1340 may also include a signal B (SIG-B) field 1326 and a data portion 1327. In a particular embodiment, the SIG-B field 1326 may be present on a per-user basis.
• the STF and LTF_1 fields may be present in both the non-precoded omni portion 1330 and the precoded MU portion 1340 to assist a receiver following an apparent channel conditions change between receipt and processing of the portions 1330 and 1340.
• the frame format selected by a transmitter may depend on the wireless network bandwidth in use. For example, only the SU frame format 1310 may be available when the bandwidth is 1 MHz, but both the SU frame format 1310 and the MU frame format 1320 may be available when the bandwidth is greater than 1 MHz (e.g., 2 MHz, 4 MHz, 8 MHz, or 16 MHz).
• timing parameters associated with the SU frame format 1310 and the MU frame format 1320 may be stored at or otherwise accessible to a transmitter and/or a receiver.
• FIG. 14 illustrates particular examples of timing parameters 1400 for the SU frame format 1310 and the MU frame format 1320.
• the timing parameters 1400 may be the timing parameters 112 and/or the timing parameters 122 of FIG. 1.
• one or more of the timing parameters 1400 of a packet may vary depending on the bandwidth (e.g., 1 MHz, 2 MHz, 4 MHz, 8 MHz, or 16 MHz) and/or number of spatial streams (1, 2, 3, or 4) in use.
• the timing parameters 1400 may include a number of complex data subcarriers N_sd, a number of pilot subcarriers N_sp, a number of total subcarriers (excluding guards) N_st, a highest subcarrier index N_sr, a subcarrier frequency spacing delta_f, an inverse discrete Fourier transform (IDFT) and DFT period T_dft, a guard interval duration T_gi, a double guard interval duration T_gi2, a short guard interval duration T_gis, an OFDM symbol duration with long intervals T_syml, an OFDM symbol duration with short guard intervals T_syms, a number of SERVICE field bits N_service, and/or a number of tail bits per binary convolution code (BCC) encoder Njail.
• BCC binary convolution code
• the timing parameters 1400 may include a STF duration for SU and MU frame formats T_stf, a LTF_1 duration for SU and MU formats T ltf 1 , a SIG field and SIG-A field duration T sig, a second LTF duration for additional LTFs T mimo ltf, a second STF duration for MU frame format T_mu_stf, and/or a SIG-B field duration T sig b.
• Some timing parameters 1400 may have different values depending on the bandwidth in use.
• the STF duration T stf, the LTF1 duration T ltf 1 , and the SIG/SIG-A field duration T_sig may each be longer when the bandwidth is 1 MHz than when the bandwidth is greater than 1 MHz.
• one or more of the timing parameters may be interrelated, as shown in FIG. 14.
• timing parameters that are derivable from other timing parameters may be omitted from a table storing the timing parameters 1400.
• FIG. 15 is a flowchart of a particular embodiment of a method 1500 of
• the method 1500 may be performed by the transmitter 1 10 of FIG. 1.
• the method 1500 may include determining, at a transmitter, that a packet is to be sent to a receiver, at 1502, and determining a wireless network bandwidth, at 1504.
• the transmitter 110 may determine that the packet 130 is to be sent to the receiver 120 and may determine (e.g., based on information from an access point or examination of messaging data) the bandwidth of the sub-1 GHz wireless network 140.
• the method 1500 may include selecting a SU frame format for use in communicating the packet, at 1506.
• the SU frame format may be the SU frame format 1310 of FIG. 13.
• the method 1500 may include selecting the SU frame format or a MU frame format, at 1508.
• the MU frame format may be the MU frame format 1320 of FIG. 13.
• the method 1500 may also include generating the packet in accordance with the selected frame format and based on one or more timing parameters associated with the selected frame format, at 1510.
• the timing parameters may be one or more of the timing parameters 1400 of FIG. 14.
• the method 1500 may further include sending the packet from the transmitter to the receiver, at 1512.
• the transmitter 110 may send the packet 130 to the receiver 120.
• FIG. 16 illustrates particular examples of tone scaling parameters 1600.
• the tone scaling parameters 1600 may be the tone scaling parameters 1 13 and/or the tone scaling parameters 123 of FIG. 1.
• tone scaling parameters may be a function of frame format (e.g., whether the packet is in the SU frame format 1310 of FIG. 13 or the MU frame format 1320 of FIG. 13), bandwidth, and/or number of spatial streams in use.
• the tone scaling parameters 1600 may include parameters for the SU frame format at 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths, including a STF tone scaling parameter, a LTF l tone scaling parameter, a SIG field tone scaling parameter, and a data portion tone scaling parameter.
• a multiple-input multiple-output LTF (MIMO-LTF) tone scaling parameter may also be applied when more than one spatial stream is in use.
• MIMO-LTF multiple-input multiple-output LTF
• the SIG field and the data portion may have the same number of available tones, and therefore the same tone scaling parameter.
• the SIG field may be generated by repeating a lower bandwidth SIG field.
• the SIG field tone scaling parameter may double (e.g., from 26 to 52, 104, 208, and 416) as the bandwidth doubles (e.g., from 1 MHz to 2 MHz, 4 MHz, 8 MHz, and 16 MHz), as shown in FIG. 16.
• the data portion tone scaling parameter may not double.
• the SIG field tone scaling parameter and the data portion tone scaling parameter may be different for some bandwidths.
• the MU frame format may not be available at 1 MHz bandwidth.
• the tone scaling parameters 1600 for the MU frame format at 1 MHz are shaded to indicate this unavailability.
• the tone scaling parameters 1600 may include a STF tone scaling parameter, a LTF l tone scaling parameter, a SIG-A field tone scaling parameter, a SIG-B field tone scaling parameter, a data portion tone scaling parameter, and a MU-STF tone scaling parameter.
• a MIMO-LTF tone scaling parameter may also be applied when more than one spatial stream is in use.
• the SIG-A field tone scaling parameter may double as the bandwidth doubles, but the SIG-B field tone scaling parameter and the data portion tone scaling parameter may not double. Thus, the SIG-A field tone scaling parameter may be different than the data portion tone scaling parameter for some bandwidths.
• the SIG-B tone scaling parameter may be the same as the data portion tone scaling parameter for each bandwidth, as shown in FIG. 16.
• FIG. 17 is a flowchart of a particular embodiment of a method 1700 of
• the method 1700 may be performed by the transmitter 110 of FIG. 1.
• the method 1700 may include selecting, at a transmitter, one or more tone scaling parameters for use in communicating a packet via a sub-1 GHz wireless network operating at a particular bandwidth, at 1702.
• the one or more tone scaling parameters may be selected based at least in part on a frame format of the packet and the particular bandwidth.
• the transmitter 1 10 may select one or more of the tone scaling parameters 1 13.
• the tone scaling parameters may be one or more of the tone scaling parameters 1600 of FIG. 16.
• the method 1700 may also include generating the packet, including scaling one or more fields of the packet in accordance with the one or more tone scaling parameters, at 1704.
• fields such as STF, LTF_1, SIG, MIMO-LTF, and/or data may be scaled by tone scaling parameters when the packet is a SU frame format packet and the bandwidths is greater than or equal to 1 MHz.
• fields such as STF, LTF_1, SIG-A, MU-STF, MIMO-LTF, SIG-B, and/or data may be scaled when the packet is a MU frame format packet and the bandwidth is greater than 1 MHz.
• the method 1700 may further include sending the packet from the
• the transmitter 110 may send the packet 130 to the receiver 120.
• a particular embodiment may utilize a single MCS table that is indexed by bandwidth, number of spatial streams, and MCS index.
• multiple tables may be used (e.g., different tables for each bandwidth, frame format, or bandwidth/frame format combination).
• more, fewer, and/or different types of data structures than those illustrated may be used in conjunction with the described techniques.
• FIG. 18 is a block diagram of a mobile communication device 1800.
• the mobile communication device 1800 or components thereof, include or are included within the transmitter 1 10 FIG. 1, the receiver 120 of FIG. 1, a transceiver, or any combination thereof. Further, all or part of the methods described in FIGS. 11, 12, 15, and/or 17 may be performed at or by the mobile communication device 1800, or components thereof.
• the mobile communication device 1800 includes a processor 1810, such as a digital signal processor (DSP), coupled to a memory 1832.
• DSP digital signal processor
• the memory 1832 may be a non-transitory tangible computer-readable
• the instructions 1860 may be executable by the processor 1810 to perform one or more functions or methods described herein, such as the methods described with reference to FIGS. 11, 12, 15, and/or 17.
• the memory 1832 may also store MCS tables 1861, timing parameters 1862, and tone scaling parameters 1863.
• the MCS tables 1861 may include the MCS tables 11 1 of FIG. 1, the MCS tables 121 of FIG. 1, the MCS tables illustrated in FIGS. 2-10, or any combination thereof.
• the timing parameters 1862 may include the timing parameters 1 12 of FIG. 1, the timing parameters 122 of FIG. 1, the timing parameters 1400 of FIG. 14, or any combination thereof.
• the tone scaling parameters 1863 may include the tone scaling parameters 113 of FIG. 1, the tone scaling parameters 123 of FIG. 1, the tone scaling parameters 1600 of FIG. 16, or any combination thereof.
• the processor 1810 may also include, implement, or execute instructions related to device components described herein.
• the processor 1810 may include or implement an encoder 1891 (e.g., the packet creator/encoder 114 of FIG. 1) and/or a decoder 1892 (e.g., the packet extractor/decoder 124 of FIG. 1).
• FIG. 18 also shows a display controller 1826 that is coupled to the processor
• FIG. 18 also indicates that a wireless controller 1840 can be coupled to the processor 1810, where the wireless controller 1840 is in communication with an antenna 1842 via a transceiver 1850.
• the wireless controller 1840, the transceiver 1850, and the antenna 1842 may thus represent a wireless interface that enables wireless
• the wireless communication may be via a sub-1 GHz wireless network (e.g., an IEEE 802.1 lah wireless network), such as the wireless network 140 of FIG. 1.
• a wireless interface may be used to send or receive the packet 130 of FIG. 1.
• the mobile communication device 1800 may include numerous wireless interfaces, where different wireless networks are configured to support different networking technologies or combinations of networking technologies.
• FIG. 18 illustrates a mobile communication device
• other types of devices may communicate via a sub-1 GHz wireless network (e.g., an IEEE 802.1 lah wireless network).
• Some devices may include more, fewer, and/or different components than those illustrated in FIG. 18.
• an IEEE 802.1 lah wireless sensor may not include the display 1828, the speaker 1836, or the microphone 1838.
• the processor 1810, the display controller 1826, the memory 1832, the CODEC 1834, the wireless controller 1840, and the transceiver 1850 are included in a system-in-package or system-on-chip device 1822.
• an input device 1830 and a power supply 1844 are coupled to the system-on-chip device 1822.
• the display device 1828, the input device 1830, the speaker 1836, the microphone 1838, the antenna 1842, and the power supply 1844 are external to the system-on-chip device 1822.
• each of the display device 1828, the input device 1830, the speaker 1836, the microphone 1838, the antenna 1842, and the power supply 1844 can be coupled to a component of the system-on-chip device 1822, such as an interface or a controller.
• an apparatus includes means for storing one or more data structures.
• the one or more data structures correspond to one or more available bandwidths of a sub-one gigahertz wireless network and one or more available spatial streams of the sub-one gigahertz wireless network.
• the one or more available bandwidths of the sub-one gigahertz wireless network include a one megahertz bandwidth.
• Each data structure indicates, for each of a plurality of MCS indexes, at least one encoding characteristic of a packet that includes the MCS index.
• the means for storing may include a component (e.g., a memory or data storage device) of the transmitter 110 of FIG.
• the apparatus also includes means for processing a packet based on a particular MCS index included in the packet.
• the means for processing may include the packet creator/encoder 1 14 of FIG. 1, the packet extractor/decoder 124 of FIG. 1, the processor 1810 of FIG. 18, the encoder 1891 of FIG. 18, the decoder 1892 of FIG. 18, another device configured to process data, or any combination thereof.
• a software module may reside in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disk, a removable disk, a compact disc read-only memory (CD-ROM), or any other form of non-transitory storage medium known in the art.
• An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor.
• the processor and the storage medium may reside in an application-specific integrated circuit (ASIC).
• ASIC application-specific integrated circuit
• the ASIC may reside in a computing device or a user terminal (e.g., a mobile phone or a PDA).
• the processor and the storage medium may reside as discrete components in a computing device or user terminal.

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• 2013
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